1. Field of the Invention
The present invention relates to an endoscope having a camera unit.
2. Description of the Related Art
An endoscopes is equipped with an insertion section that is inserted into the inside of a subject's body, and a hand operating section that is connected to a base end of the insertion section. The insertion section is consisted of a tip portion, a bending portion, and a soft portion, which are provided consecutively from its tip. The bending portion has a structure in which a plurality of bending pieces are coupled together, and is bendingly operated by a bending operation wire provided inside bending pieces being pushed and pulled, and the orientation of a tip portion thereof is changed.
The tip portion of the insertion section is equipped with an observation window, an illumination window, a fluid jet nozzle, a treatment tool outlet, and the like. A camera unit for imaging the inside of a subject's body is provided in the back of the observation window. The illumination window allows illumination light to be radiated toward an imaging range of the camera unit therethrough. The fluid jet nozzle has a jet port at a tip thereof, and selectively jets, for example, liquids, such as cleaning water, or gases, such as air or carbon dioxide gas. A liquid jetted from the fluid jet nozzle flushes dirt on the observation window, and a gas blows away droplets remaining on the surface of the observation window. Various treatment tools are protruded from and retracted into a treatment tool outlet. Various kinds of treatment are performed with respect to affected parts by the treatment tools. Additionally, the treatment tool outlet also serves as a suction port, and when a treatment tool is not inserted through the treatment tool outlet, body fluids, filth, or the like is sucked from an affected part.
The camera unit has an optical system consisting of a plurality of optical components, such as a lens and a prism, and an imaging element, such as a charge-coupled device (CCD) that photoelectrically converts an optical image focused by the optical system into imaging signals. The imaging element is connected to a signal cable via a flexible substrate, a sub-substrate, and the like. Additionally, electronic components are mounted on the flexible substrate or the sub-substrate so as to drive the imaging element. Signals from the camera unit are sent to an image processor via the flexible substrate, the sub-substrate, and the signal cable. The image processor processes the signals, and thereby an image of a lesioned site and the like, is displayed on a monitor.
The signal cable that sends the signals from the camera unit to the image processor is constituted by a composite multi-core cable. Since this signal cable is inserted through an insertion section over its entire length, the signal cable is strongly pushed and pulled whenever the insertion section is looped or bent. For this reason, the camera unit is firmly attached to the tip portion, using various fixing means. The fixing means include: a fixing screw or an adhesive (refer to FIG. 5 of JP1996-136829 (JP-H08-136829A), FIG. 2 of JP2000-37343A, and FIG. 22 of JP2007-330806A); the fitting between a projection and a recessed groove (refer to FIG. 6 of JP2001-83436A), fixing with pressure using a fixing member (refer to FIG. 10 of JP2002-58635A).
For example, as in endoscopes described in JP1996-136829 (JP-H08-136829A) and JP2000-37343A, a camera unit is attached to an attachment hole by attaching a fixing screw to a fixing screw hole provided in a tip portion after a lens frame of the camera unit is inserted into a camera unit attachment hole provided in the tip portion.
In an endoscope described in JP2007-330806A, a V-shaped groove is formed in an outer peripheral portion of a lens frame of a camera unit, and a fixing screw hole is formed in an attachment hole of the lens frame of a tip portion. After the lens frame of the camera unit is inserted into the attachment hole, the tip of the fixing screw is pressed against a tip-side inclination surface of the V-shaped groove by screwing the fixing screw to the fixing screw hole. Accordingly, the camera unit is screw-fastened and fixed in a state where the camera unit is pushed against the attachment hole to the tip side.
In an endoscope described in JP2001-83436A, a tip portion is constituted by a holding portion and a cover portion, and a recessed groove is formed in an outer peripheral surface of the holding portion. A camera unit is inserted into the recessed groove. Additionally, a positioning recess is formed in the recessed groove, and a projection is provided on the camera unit. The camera unit is fixed to the tip portion by the fitting between the projection and the positioning recess.
In an endoscope described in JP2002-58635A, a fixing member is screw-fastened and fixed to a tip portion, in a state where a camera unit is pressed against and fixed to a housing hole of the tip portion, using the fixing member.